Malayalam needs to support the Unicode 8.0 Virama and joiner sequences

[roozbehp]

Unicode 8.0 adds a mechanism for selecting various forms of Malayalam conjuncts. The actual Core Specification is still pending publication (it will be available in a few weeks), but until then, the best documentation available is at http://www.unicode.org/review/pri263/pri263-malayalam.pdf.

Assigning to @cibu to provide a complete list of needed conjuncts and the sequences that are supposed to generate them, so they could be added to the fonts.

CC-ing @behdad and @JelleBosmaMT in case any changes may be required to HarfBuzz.

[behdad]

No HarfBuzz changes should be needed. Jelle, let me know if you need anything.

[behdad]

[well, we need to update the indic shaper's data table for Unicode 8.

[roozbehp]

@behdad, this shouldn't need any update to the shaping tables. There's no new characters, just new sequences that used to have undefined behavior before, but is now specified to form certain forms of conjuncts.

[behdad]

@roozbehp Ok I thought there's a new virama character involved...

[JelleBosmaMT]

The existing fonts already support ligatures with U-200D + virama. That is
a set of “optional” ligatures that work with and without ZWJ and
“exclusive optional” that work with ZWJ only. Not sure how much else is
needed. It may be problematic to try and develop an 8 master Malayalam
font that is both document and UI and both traditional and reformed all at
the same time.

On 09-aug.-15 14:23, "Behdad Esfahbod" notifications@github.com wrote:

@roozbehp https://github.com/roozbehp Ok I thought there's a new virama
character involved...
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[cibu]

Supporting the spec for optional ligatures can be lot of work for reformed orthography fonts like Noto Malayalam Sans; as many additional glyphs available in an traditional orthography script needs to be supported. For example, KA + ZWJ + VIRAMA + RA should return a connected ligature.

So question would be how much more are we willing to draw. Depending on the answer we can come up with a subset of relevant traditional ligatures.